Created on 05/04/2015 12:29 PM.
Last updated on 16.02.2020 16:15.
Author: Pavel Sayk.
Recently, “ABw” has begun to pay more attention to car audio systems. Despite the introduction to the topic, which preceded a series of reviews and tests of car radio and CD-receivers, the editorial office began to receive calls with questions.
We took them on a pencil. And today we will pay attention not to specific devices, their capabilities and sound quality, but to common truths, on ignorance of which, as a rule, motorists stumble. Should we believe the capacity data given by the manufacturers?
It shouldn’t be too important to attach great importance to the power of audio equipment. This is often just a manufacturer’s advertising gimmick. Even a student knows that electrical power is determined by the voltage and resistance of the load. As you know, the voltage in the car network is 12 volts.
At high generator speeds (while driving), the voltage on board the car can jump to 14 volts. The ceiling is 14.4 volts.
At the same time, all manufacturers of automotive equipment lay down the maximum calculated resistance value for acoustics of 4 ohms. Simple calculations will convince you that in such conditions, according to Ohm’s law, the radio tape recorder will give out about 52 watts per channel.
All normal power measurements of the apparatus are made on a sinusoidal signal. Only in automobile “heads”, and even in Chinese “soap dishes”, they indicate the peak power, which for a sinusoidal signal is twice (or even more) higher than the average.
The average power for an ideal bridge amplifier is calculated from the effective voltage of the on-board network, i.e. 12V / 2 = 8.484V.
And the average power is, respectively, 8,484? / 4 = 18 W. And this is in theory. In practice, even less.
Also, remember that this is the peak value. The amplifier of the radio tape recorder at this voltage will last for a short time. Despite the fact that all manufacturers of acoustics make it with a margin, at peak power the speaker is also unlikely to last more than 5 minutes. Therefore, all sellers of automotive equipment strongly recommend adhering to the nominal power, the distortion at which does not exceed 10-15%. Only in this case will the music really please the ear.
More powerful amplifier means better?
So, we found out that the power is needed as much as the acoustics can convert into sound without distortion. In this case, one should not forget about such a factor as the power balance.
Do not be surprised when, instead of the standard radio, you put a modern CD-receiver and hear that the sound has become worse: you have violated the power balance.
Alas, later you will have to splurge on decent acoustics.
A small woofer has the hardest part to reproduce bass. When a lot of bass is brought in, even very decent acoustics will wheeze at high power. Therefore, to obtain an optimal balance, a signal without bass is output to the “front”, and speakers with a large diffuser area are installed on the “rear”, to which the signal is output with a slight excess of bass.
Moreover, it is preferable to have speakers of a round shape. They emit a sound wave with less distortion than oval ones.
For these purposes, it is better to choose “twenty” (20 cm in diameter). Look, the sound changes dramatically. The front speakers will get rid of overload, the sound will acquire clarity and brightness, and the rear ovals add missing bass to the soundstage.
Everything would be good, but such a “weight distribution” of the bass can be done only by amplifiers of radio tape recorders or Pioneer CD-receivers (FIE, SFEQ functions). The rest, to achieve such a sound, cannot do without external amplifiers with crossover filters and power converters.
What are the criteria for choosing car audio?
In this matter, the most important thing is to understand what you expect from the car audio system: will you limit yourself to replacing the head unit and speakers, or subsequently supplement the system with an external amplifier and subwoofer.
Unfortunately, it is not possible to check the characteristics of acoustics in “field” conditions.
Therefore, you have to take the manufacturers’ word for it.
A number of factors affect the price tag and sound quality: the materials of the magnet, diffuser, suspension, the type of system, as well as the sensitivity of the acoustics. Many car enthusiasts make a serious mistake by purchasing high-sensitivity speakers with an amplifier. It’s just money thrown away.
The appearance of the speaker itself can tell a lot about acoustics based on ferrite magnets. The greater the mass of the magnet, the more power can be supplied to the speaker and the higher the rated power bar. True, there are exceptions to the rule. Take, for example, Morel acoustics.
It is based on completely different technologies. Moreover, such speakers are lighter and have much better performance. However, only a select few will be able to afford such acoustics: the cost of some systems exceeds $ 1000.
Is it better to use two-, three- or four-way speakers for high-quality sound?
This is perhaps the most frequently asked question when designing a high quality car audio system. Let’s make a reservation right away that coaxial frontal acoustics are not suitable for these purposes. The only exception can be two-way coaxial loudspeakers as combined mid / high frequency emitters.
Two-way component front speakers, like any compromise design, also have their drawbacks: getting the right soundstage and good balance is difficult. Most of all, for these purposes, a multi-band dispersed front-facing audio system is suitable. Moreover, the word “many” means rather “three”, since a broad offensive of four-lane systems is not expected in the near future.
It should also be added that getting high-quality sound is a difficult task.
Almost every car requires an individual approach and a whole range of works, which may include noise and vibration isolation of the passenger compartment, preparation of speaker installation sites, laying of better wiring, etc. There are many pitfalls here, and the result depends on the skill of the installer, the desire and financial capabilities of the car owner.
What brand of CD-Receivers have the best anti-shock properties?
First, you need to figure out what an “anti-shock” is. The audio signal is first driven into the CD-receiver’s memory, processed in the processor, and only then playback follows. Devices with digital “anti-shock” are almost impossible to unbalance.
Not without, however, a fly in the ointment.
The sound in such devices loses color, detail, becomes more digital.
When listening to electronic music, even a thin ear will not catch the catch. But on jazz, blues, rock, classical and even “pop” this “dryness” will be noticeable. Perhaps that is why digital “anti-shock” is used extremely rarely in car players (as a rule, in expensive models). The term vibration resistance is more suitable for the anti-shock mechanisms of devices of the budget and middle class.
The CD drive for such models is mounted on a special …